The results of new study suggests men become less frugal and more impulsive when they perceive a scarcity of females. It’s a behavior that is not unique to humans, researchers said.

“What we see in other animals is that when females are scarce, males become more competitive. They compete more for access to mates,” said Vladas Griskevicius, Ph.D., an assistant professor of marketing at the University of Minnesota and lead author of the study.

“How do humans compete for access to mates? What you find across cultures is that men often do it through money, through status and through products.”

Researchers tested the theory that the sex ratio affects economic decisions, by having participants read news articles that described their local population as having more men or more women.

They were then asked to indicate how much money they would save each month from a paycheck, as well as how much they would borrow with credit cards for immediate expenditures. When men were led to believe women were scarce, the savings rates for men decreased by 42 percent. Men were also willing to borrow 84 percent more money each month.

In another study, participants saw photo rolls of men and women that had more men, more women, or were neutral.

After looking at the photographs, participants were asked to choose between receiving some money tomorrow or a larger amount in a month. When women were scarce in the photos, men were much more likely to take an immediate $20 rather than wait for $30 in a month.

Researchers said such behavior occurs subconsciously — that participants were unaware that sex ratios were having any effect on their behavior. Merely seeing more men than women automatically led men to simply be more impulsive and want to save less while borrowing more to spend on immediate purchases.

“Economics tells us that humans make decisions by carefully thinking through our choices; that we’re not like animals,” said Griskevicius.

“It turns out we have a lot in common with other animals. Some of our behaviors are much more reflexive and subconscious. We see that there are more men than women in our environment and it automatically changes our desires, our behaviors, and our entire psychology.”

Researchers then flipped roles in the study to see if sex ratios would influence the financial choices of women. They learned that although ratios did not influence how women spent their money, they do shape women’s expectations of how men should spend their money when courting.

For example, when women learned that males were in the majority, the women expected men to spend more on dinner dates, Valentine’s gifts, and engagement rings.

“When there’s a scarcity of women, women felt men should go out of their way to court them,” said Griskevicius.

In a male-biased environment, men also expected they would need to spend more in their mating efforts.

Researchers next decided to test their hypothesis with a review of real world data. To do this, they calculated the sex ratios of more than 120 U.S. cities and discovered that in communities with an abundance of single men, men showed greater ownership of credit cards and had higher debt levels.

One striking example was found in two communities located less than 100 miles apart. In Columbus, Ga., where there are 1.18 single men for every single woman, the average consumer debt was $3,479 higher than it was in Macon, Ga., where there were 0.78 single men for every woman.

Griskevicius said the effects of sex ratios go beyond marketing and influence all sorts of behavior. He cites other studies showing the strong correlation between male-biased sex ratios and aggressive behavior.

“We’re just scratching the tip of the iceberg when it comes to financial behavior,” said Griskevicius. “One of the troubling implications of sex ratios for the world in general is that it’s about more than just money. It’s about violence and survival.”

APA Reference
Nauert, R. (2012). Men Spend More When Women are in Demand. Psych Central.
Retrieved on March 3, 2015, from http://psychcentral.com/news/2012/01/13/men-spend-more-when-women-are-in-demand/33637.html